Continued from yesterday’s entry (Part 5)
A good solution for the job: JPEG
One of the most recognized and most universally accepted formats for photography the .jpg or JPEG file format. (Pronounced Jay-Peg) It is supported in web browsers and most image viewing applications and it’s a great solution for storing images because of its ability to compress an image and still look great. The JPEG format is very widely used and accepted so it should be considered as an important part of your archive solution.
That said, there are some major drawbacks that we need to point out. First off JPEG files use “lossy” compression. Now, read the word carefully. I said “lossy” not “lousy”. “Lossy” means that every time you save your image you loose some data and the image degrades. Even if you save your image at 100% quality you are still losing infomation because of this compression. Another issue to keep in mind is the fact that every time you edit your image and save it again you are losing more quality. So as an archiving solution JPEG files should not be your first choice but a solution for easily and quickly viewing your final images. At the very least you need to keep an original JPEG file as a master and save files from the master each time you make edits. I would suggest investigating other “non-lossless” formats for archiving your original image files though and always working from those files when editing your image if possible. Then once you are happy with the final image, save another version as a compressed JPEG for quick reference and viewing later.
The new JPEG 2000 format is gaining popularity and it promises higher quality images but it is still “lossy” and will not retain all the original image information. Not to complicate things further but to clarify a common rummor, there is actually a “lossless” JPEG format but it doesn’t compress nearly as well as the standard baseline JPEG format. Currently the “lossless” JPEG is a good example of an extinct file format because it is no longer supported by most major applications. There is also another new version called JPEG-LS which is also a lossless format but your guess is as good as mine if this format will ever catch on with the masses. Standard baseline JPEG is a wonderful format to work with when the job is right but as a pure archive format you should consider something lossless.
The RAW format: Highest quality, smallest size, but risky.
Another popular option is the RAW format. The RAW format is popular because it’s the closest you will get to a digital negative. It is simply the data that comes straight from your CDD. (Charged Coupled Device — One of the two main types of image sensors used in digital cameras) The advantage of this format is that the image can be saved in a lossless format that is considerably smaller in file size than TIFF (discussed next) which is important to some people but the main reason photographers choose this format is that the image has not been processed or modified by the camera settings in any way. You are starting with the raw data that the camera collected when you tripped the shutter. In my opinion there are some good points to using RAW as an arhive format but there is one main drawback and it is a big one. You can’t open this format with a normal photo program. You need to use what is called an “acquire module” that allows you to access the file via a plug-in for your software. The most common used module is TWAIN which installs into your image editor and brings the image into your software.
Doesn’t sound so bad right? Well, the kicker is that there is no universally accepted standard RAW format yet. In fact each camera maker and sometimes each camera has it’s own format. So if you are in agreement with me so far that we only want to dedicate ourselves to popluar formats that are widely used and will stand the test of time, RAW is not my top choice for archiving my images just yet.
There has been news lately about a standard proposed by Abobe — the DNG (Digital Negative) which will be a new, publicly available archival format for the raw files generated by digital cameras. By addressing the lack of an open standard for the raw files created by individual camera models, DNG helps ensure that photographers will be able to access their files in the future.
This new format hasn’t been adopted officially yet so in the meantime keep your eyes and ears open for more news on DNG formats at ArchivingDigital.com but at this point I would recommend shooting in RAW format mode and then immediately converting all your images to another “lossless” image format like .PNG or TIFF for archiving. (Discussed next)
The winner, hands down: TIFF
TIF or TIFF is widely considered the standard for digital photo archiving. TIFF stands for Tagged Image File Format and it is universally accepted on all popular platforms like PC, Macintosh, Unix along with most major image editing applications. TIFF is pretty much hands down the best solution for archival purposes at this point and I can’t say enough about it. TIFF files use LZW “lossless” compression (Lempel-Ziv-Welch – Named for the inventor) which means that the original information in the photograph is saved exactly as it was taken even though the image is being compressed. LZW Compression in TIFF files is more effective in continuous tone images than photographic images, and also more effective when dealing with black and white images than full color images.
There are only a few minor drawbacks to using TIFF files and they are unavoidable. First off, some free or lower cost image editing programs will not support TIFF due to the fact that LZW compression requires a royalty to be paid to the patent holder. So some companies don’t support TIFF for this reason alone. Most popular and widely used professional programs like Adobe Photoshop (www.adobe.com) support TIFF and it should not deter you from using the format unless you can’t find an affordable solution for image editing. If you are at all concerned about editing and archiving your images make the investment and purchase a quality program like Photoshop or something similar.
The second issue to keep in mind is the fact that TIFF files are rather large. This is really a curse and a blessing because with large file size comes high quality, detailed information that builds beautiful photos. The downside is that TIFF files can tax your storage solutions. A TIFF file is sometimes 20 times larger than a JPEG file and can eat up gigs and gigs of storage space quickly. The good news is that storage is generally affordable and getting cheaper every day. A few years ago you might pay $200 for a gig of storage space. I remember my first computer had a grand total of 250 megs on it! Today for less than $250 you can get 60-100 gig Firewire hard drives that make temporarilly storing your images affordable and fast.
To sum up this discussion, use JPEG for quick viewing, web presentations and sharing of your photos and stick to RAW converted to TIFF as a standard archive format whenever possible. It will be a very long time before before TIFF is replaced or becomes extinct. There are billions and billions of important government documents that are stored in this format. Not to mention all the commercial and consumer photography stored in this manner. So, for the purpose of choosing an archive solution TIFF wins hands down. It’s a safe bet that TIFF will be around for a very long time into the future.
One to consider: The PNG Format
The PNG file format (Pronounced PING) is gaining popularity around the world. Users are discovering the power of the PNG format and also its affordability which makes it very popular among developers. PNG is a royalty-free format that was invented to replace LZW TIFF and its royalites. It is important to note because of its growing popularity but mostly because of its compression efficiency. PNG provides “lossless” compression at 25% less file size than TIFF plus the added bonus of possibly being supported by web browsers in the near future and offering transparent pixel values. The bad news is that these features have yet to catch on officially and we are still waiting and guessing to see what happens. Your bet is as good as mine on this one but it does show a lot of promise.
Again, our purposes here are to archive our photography, not jump on the latest popular or potential trend and guess as to what the future holds. The last thing you want to do is bet on a horse that ends up coming in last 20 years from now.
For more news on this subject or to start a discussion visit ArchivingDigital.com!
Coming up next:
(Part 7) DPI vs. Pixels What are we talking about?